Exhibit 10.20





Amendment to the OPTION AND JOINT VENTURE AGREEMENT


Of March 15th, 2001





It is hereby agreed this 14 day of May, 2002, to amend the OPTION AND JOINT VENTURE AGREEMENT of March _15
, 2001, (The Agreement) between MINERA ANDES INC., a corporation formed under the laws of Canada (MAI), MINERA ANDES S.A., a corporation formed under the laws of
Argentina (MASA) and MAURICIO HOCHSCHILD & CIA. LTDA., a corporation formed under the laws of Peru (MHC).





By
mutual consent as witnessed by the signing of this document it is hereby agreed that Rights as defined under the preamble of The Agreement and more particularly described in Schedule A of The Agreement will be modified effective as of
May 15, 2002 to the areas of interest described in Exhibit 1.





Also, by mutual consent as witnessed by the signing of this document it is
hereby agreed that MHC will hereafter take over the responsibilities of maintaining the Rights described in Exhibit 1as defined under section 7.1.4 (f) of The Agreement.





Neither party shall take any action during the Option Period to exclude from the Property any portion or parcel of the Rights described in Exhibit 1 without the consent of the other party, except in
accordance with the procedure state in Section 7.2 of The Agreement.





IN WITNESS WHEREOF the parties have executed this Agreement as of
the day, month and year first above written.





MINERA ANDES INC.





By:

/s/    Allen V. AmbroseIts:

President





MINERA ANDES S. A.





By:

/s/    Jorge VargasIts:





MAURICIO HOCHSCHILD & CIA. LTD.





By:

/s/    Jorge BenavidesIts:




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EXHIBIT 1





PROPERTY TYPE

FILE

AREA REAL

CommentsEl Pluma 1

410.411/MA/99

750

Ex cateo 402.845El Pluma 2

412.277/MA/99

1000

Ex cateo 402.845El Pluma 3

412.279/MA/99

750

Ex cateo 402.845El Pluma 4

412.281/MA/99

1000

Ex cateo 402.845El Pluma E1

410.412/MA/99

1000

Ex cateo 403.627El Pluma E2

412.278/MA/99

1000

Ex cateo 403.627El Pluma E3

412.280/MA/99

800

Ex cateo 403.627Saavedra 10

413.395/MA/00

1000

in cateoSaavedra 11

401.874/MA/01

1000

in cateoSaavedra 12

401.875/MA/01

1000

in cateoSaavedra 13

401.876/MA/01

1000

in cateoSaavedra 14

401.877/MA/01

1000

in cateoSaavedra 1a

410.093/MA/99

1000

in cateoSaavedra 2a

410.091/MA/99

1000

in cateoSaavedra 3

410.096/MA/99

800

ex cateoSaavedra 4

410.095/MA/99

800

in cateoSaavedra 5

410.089/MA/99

800

in cateoSaavedra 6b

410.094/MA/99

800

ex cateoSaavedra 7a

410.090/MA/99

1000

in cateoSaavedra 8

410.092/MA/99

1000

in cateoSaavedra 9

413.396/MA/00

1000

in cateoSaavNE1

400.625/MA/01

1000

ex cateoSaavNE2

400.626/MA/01

1000

ex cateoSaavNE3

400.627/MA/01

500

ex cateoTres A

411.333/MA/99

1000

ex cateoTres B

411.334/MA/99

750

ex cateoTres C

414.264/MA/00

980

ex cateoTres Colores A

411.332/MA/99

1000

Ex cateo 406.002Tres Colores B

411.331/MA/99

998.5

Ex cateo 406.002Tres Colores C

414.643/MA/00

901

Ex cateo 406.002Tres Colores D

414.642/MA/00

901

Ex cateo 406.002Tres Colores E

414.641/MA/00

901

Ex cateo 406.002Tres Colores F

414.640/MA/00

901

Ex cateo 406.002Tres Colores G

414.639/MA/00

397.5

Ex cateo 406.002Tres D

414.265/MA/00

770.13

ex cateoTres E

414.266/MA/00

999.93

ex cateoTres F

414.267/MA/00

999.93

ex cateoUno A

413.095/MA/00

840

ex cateo






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Uno B

413.096/MA/00

840

ex cateoUno C

413.097/MA/00

820.2

ex cateoUno D

400.765/MA/01

840

ex cateoUno E

400.766/MA/01

840

ex cateoUno F

400.764/MA/01

594

ex cateoUno G

401.507/MA/01

1103.7

ex cateo 406.943Uno H

401.508/MA/01

560.4

ex cateo 406.943Uno I

401.509/MA/01

560.4

ex cateo 406.943AGUAS VIVAS

403.089/MSC/01

999250490.69






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